DNS is heavily cached throughout the internet, but I think we overestimate how efficient these distributed caches are. For example, Yahoo found that 40-60 percent of their users have an empty browser cache experience. There is value in having a fast, distributed core service for the no-cache scenario.

A brief discussion of our use of virtual machines in our little server farm. Since the only trouble spot for VM performance is disk, that gives us the flexibility of using a lot of great Linux and open source tools for networking (no or very little disk dependency), such as HAProxy and Cacti.

When it comes to Stack Exchange, the broader the topic, and the more unanswerable questions you have, the worse the engine will do for you. The engine is designed for reasonably narrow topics, with a majority of questions that can actually be answered in some reasonable way.

Joel likens the classic divide in software developers to “library users versus library writers”. At what point do programmers cross that chasm? Do they need to? Joel says “we write one algorithm per year.”

How do you deal with the dancing bunnies problem? Also known as the Dancing pigs problem. “Given a choice between dancing pigs and security, users will pick dancing pigs every time.”

We answered the following listener questions this week:

Steve: “The etiquette rules for meta are much looser than on the other Trilogy sites. Does this have ramifications for Stack Exchange sites?”

Brian: “Technology changes so fast that most developers burn out in 20 years. How do we retain our historical knowledge if the rate of attrition is so high?”

If you’d like to submit a question to be answered in our next episode, record an audio file (90 seconds or less) and mail it to podcast@stackoverflow.com. You can record a question using nothing but a telephone and a web browser. We also have a dedicated phone number you can call to leave audio questions at 646-826-3879.